Ostrich dinosaurs invade Europe! Or do they?

Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

Hastily 'updated' version of a Wessex Formation scene, now with ornithomimosaurs! 'Angloposeidon' in the background, Eotyrannus (with an Ornithodesmus) on a buttress root. Image by Darren Naish.

Regular readers of Tet Zoo might know that I’ve published extensively on the theropod dinosaurs of a famous and much-studied Lower Cretaceous rock unit known as the Wealden Supergroup. Wealden rocks range in age from Berriasian to Aptian (that is, they were deposited between about 145 and 120 million years ago) and are most famous for their exposures on both the Isle of Wight and the south-eastern part of the English mainland. The Wealden spans such a huge range of time that whole dynasties of animals came and went over the course of its deposition: there was no ‘Wealden age’ with a single set of contemporaneous animals.

Swamps, deltas, floodplains and semi-arid woodlands covered much of western Europe during Early Cretaceous times*, and among the many animals that lived here were such iconic Early Cretaceous dinosaurs as iguanodontians, polacanthids and titanosauriform sauropods. Wealden theropods include the spinosaurid Baryonyx, the carcharodontosaurian Neovenator and the tyrannosauroid Eotyrannus.

* For those who still find it confusing, the terms ‘Early’ and ‘Late’ mean different things from ‘Lower’ and ‘Upper’ when discussing the geological past. ‘Early’ and ‘Late’ refer to time (e.g., Iguanodon lived during the Early Cretaceous) whereas ‘Lower’ and ‘Upper’ refer to stratigraphy (e.g., Iguanodon is a Lower Cretaceous fossil, found in Lower Cretaceous rocks).

If you're interested in Wealden dinosaurs, it might be a good idea to own these two books. They're both surprisingly affordable.

The stratigraphy of the Wealden is complicated and it’s taken decades for us to devise a system that experts agree on. The oldest strata belong to what’s known as the Hastings Group (deposited between the Berriasian and Valanginian, right at the start of the Cretaceous), while the younger ones at the top belong variously to the Weald Clay Group or the Wealden Group. Familiar Isle of Wight Wealden dinosaurs like Neovenator, Polacanthus and Mantellisaurus come from the Wessex Formation, the most fossiliferous and accessible Wealden unit. Deposited predominantly during the Barremian, the Wessex Formation is part of the Wealden Group. Note that ‘Wealden Group’ and ‘Wealden Supergroup’ refer to very different things. The stratigraphic chart below might help. If you really want to understand all of this in greater depth, see the several relevant chapter in Batten (2011).

My handy chart of Wealden stratigraphic terminology. Most of the animals discussed in this article are from the Wessex Formation, deposited during Barremian times. Valdoraptor (discussed below) is most likely from the Grinstead Clay Formation, and hence is Valanginian in age.

Theropods in the Wealden… again

Anyway, theropod fossils are not common in the Wealden – they’re rare enough that virtually every single record is worth writing up and interpreting (err, in my opinion, anyway). And while Neovenator, Eotyrannus and Baryonyx are all known from decent associated partial skeletons, the majority of Wealden theropod records are scrappy, consisting of the odd vertebra, limb bone, or tooth.

Harry Seeley (1839-1909) and Richard Lydekker (1849-1915): two gentlemen who left us with some grand taxonomic messes... like that depicted in the scribbled flow-chart shown below.

When you combine this scrappy record with the fact that British scientists were interpreting these fossils at a time when virtually nothing was known of theropod anatomy, diversity or phylogeny, it’s not surprising that a confusing and very messy picture developed. Victorian scientists like Richard Owen, Harry Seeley and Richard Lydekker proposed new names for these fossils, synomised the names proposed by their colleagues, un-synonymised the proposed synonomisations of others, referred new specimens to certain taxa they’d named beforehand, and generally left a gargantuan mess that few people understand and even fewer care about.

What sorts of theropods do these scrappy specimens represent? Since finishing my 1999 MPhil work on this particular set of dinosaurs, I’ve made a cottage industry of interpreting and reinterpreting them, variously suggesting the presence of abelisauroids, indeterminate tetanurans, non-carcharodontosaurian allosauroids, non-neovenatorid carcharodontosaurians, compsognathids, tyrannosauroids, oviraptorosaurs, dromaeosaurids, troodontids and birds (Hutt et al. 2001, Naish et al. 2001, Naish & Martill 2002, 2007, Naish 2002a, 2003, 2011, Naish & Sweetman 2011). Of course, I’m hardly the only author to have worked on, or expressed opinions on, these fossils (e.g., Harrison & Walker 1973, Norman 1990, Howse & Milner 1993, Norell & Makovicky 1997). Anyway, some of these proposed identifications are almost certainly wrong, and I increasingly think that they serve as cautionary tales with respect to how confident we should be when interpreting scrappy fossils (and… cough Samrukia cough).

The 'Holy-Grail-o-saurus Hypothesis', with Eotyrannus as the template. It has failed: those different Wealden theropods really are from different Wealden theropods. This illustration is a slide from a talk I gave in 2013.

One of my great hopes for these scrappy Wealden theropods is that some, most or even all of them might prove to be different parts of the same one animal, a sort of Holy-Grail-o-saurus that combines the foot named Valdoraptor, the neck vertebrae named Calamosaurus and Thecocoelurus, the sacrum named Ornithodesmus, and so on. It was hoped that Eotyrannus, discovered in 1997, preliminary described in 2001 (Hutt et al. 2001), and described in full in a soon-to-be-published monograph*, would be that ‘Holy Grail’ but, nope, it proved to be a wholly new taxon, definitely distinct from the other Wealden taxa. Then there’s That Which Cannot Be Named, another associated Wessex Formation coelurosaur, currently in private hands and unavailable for study. Contra expectations, it, again, doesn’t tie together any of the named bits and pieces, at least not so far as I can tell from my two brief examinations of it.

More proof that the Eotyrannus monograph really exists. This montage shows some (not all) of the illustrations included in the final work (Naish & Cau, submitted).

* People who follow me on twitter (@TetZoo), or who follow research on tyrannosauroids or Wealden theropods specifically, will know that (with co-author Andrea Cau) I finished the Eotyrannus monograph some considerable time ago. It’s since sat in limbo. However, things are progressing and it will appear in print at some stage.

Finally, we come to the reason for this article. Those of you who keep up with the happening world of Lower Cretaceous European coelurosaurs will know that Ronan Allain and colleagues have recently discovered a theropod bonebed in the Hauterivian or Barremian strata of Angeac, in Charente, southwestern France. The site, already known for the remains of a gargantuan sauropod and assorted other Cretaceous vertebrates (Néraudeau et al. 2012), has yielded more than 850 bones, representing “at least 20 individuals”, of the same coelurosaurian theropod taxon [adjacent image from this article]. A long paper describing this animal in detail is, so I understand, somewhere in the works. Meanwhile, a new publication has just appeared that presents a preliminary investigation of this animal and its implications (Allain et al. 2014). I’ve known about this work for a while and am very pleased to see it out.

What sort of coelurosaur is this animal? A toothless, anteriorly downturned dentary, ventrally flattened pedal unguals and other characters show that it’s an ornithomimosaur, an ostrich dinosaur (Allain et al. 2014). It doesn’t yet have a taxonomic name, so for now we’re just going to have to call it ‘the Angeac ornithomimosaur’.

An illustration from 2002, depicting (at top) the smaller theropods then thought to be known from the Wessex Formation and - at bottom - those suggested to perhaps be present and awaiting discovery. The ornithomimosaur is based on the Spanish Pelecanimimus. Image from Naish (2002b). It was 2002, so the animals are not shown as feathery enough (except the bird).

So, we have a definite ornithomimosaur in the Hauterivian or Barremian of France. Ornithomimosaurs are already known from the Lower Cretaceous of western Europe, as – since 1994 – we’ve been aware of the remarkable Pelecanimimus polyodon from the Barremian Calizas de la Huérguina Formation of Las Hoyas, Spain. The Calizas de la Huérguina Formation seemingly includes at least a few taxa that are also present in the similarly-aged Wessex Formation of England (including Baryonyx), so for this reason I once suggested that Pelecanimimus or a similar taxon might await discovery in the Wessex Formation too (Naish 2002b, Naish et al. 2001). That prediction hasn’t been borne out (yet), but the raison d’etre of the new paper is to show that several Wessex Formation theropod elements, and specimens from elsewhere in the Wealden succession, also represent ornithomimosaurs, and, furthermore, ornithomimosaurs that are just about identical with the Angeac ornithomimosaur (Allain et al. 2014). Note, incidentally, that the Angeac ornithomimosaur is a toothless ornithomimosaur, and thus not a close relative of Pelecanimimus.

Is the hypothesis of an oviraptorosaurian Thecocoelurus completely dead? Maybe, maybe not. Calamosaurus and a Wessex stegosaur play bit-parts. Image by Darren Naish, colouring by Patrick Murphy. The illustration is from 2001, hence the sparse feathering.

To reiterate, the reason that this French discovery – remember, it is not a Wealden dinosaur – is a big deal as goes Wealden dinosaurs is that Allain et al. (2014) argue that several Wealden theropod specimens are so similar to the Angeac ornithomimosaur that they very probably represent the same sort of dinosaur. In fact, Allain et al. (2014) argue that a whole load of previously problematic Wealden theropod remains all belong to this new kind of ornithomimosaur. Valdoraptor (named for a metatarsus from the Hastings Group) is an ornithomimosaur very similar to the Angeac taxon, so is Thecocoelurus (named for a cervical vertebrae from the Wessex Formation), and so is the famous ‘Calamosaurus tibia’ and several other Wessex Formation hindlimb elements (Allain et al. 2014).

The important message is that these fossils were all previously interpreted as belonging to very different sorts of theropods. In the most recent review of Wealden theropods, I have Thecocoelurus as a possible abelisauroid, Valdoraptor as an indeterminate neotetanuran, and the ‘Calamosaurus tibia’ as a possible tyrannosauroid or compsognathid (Naish 2011).

Problems from the Wealden 1: Thecocoelurus

Thecocoelurus compared with a cervical vertebra of Falcarius: an image prepared for a manuscript I ended up abandoning. aas = anterior articular surface; apf = anterior peduncular fossa; ilf = interspinous ligament fossa; nc = neural canal; vr = ventrolateral ridge. Scale bar = 20 mm. UPDATE: this figure might be misleading, in that the Thecocoelurus image A is of the anterior end, but I think the Falcarius image B is of the posterior end!

If this is right, then the Angeac ornithomimosaur really is the Holy-Grail-o-saurus of the sort mentioned above… though note that there are still other Wealden theropods that aren’t part of this story and – so far as we can tell – do still represent other clades: Becklespinax, Calamosaurus, Aristosuchus, the Ashdown maniraptoran, Wyleyia and Ornithodesmus, for example.

But… is it right? Allain et al. (2014) regard Thecocoelurus (remember: based on half of a single cervical vertebra) as “morphologically identical” to vertebrae of the Angeac ornithomimosaur. I was initially happy to take their word for this, but a detailed look at their figures shows that, while similar, it’s difficult to be convinced that the vertebrae really are “identical”. The problem is that the cervical vertebrae of quite a few distinct theropod groups are highly similar, similar enough that you can be semi-convinced by general comparisons, but less satisfied when all the anatomical minutiae are compared in detail. Hence Thecocoelurus has found itself purportedly sharing specific characters with caenagnathid oviraptorosaurs (Naish & Martill 2002), Falcarius the therizinosaur (Kirkland et al. 2004), noasaurid abelisauroids (Naish 2011), and now with ornithomimosaurs. Mickey Mortimer compared the cervical vertebrae of these groups in his blog article here. The takehome?…

Yes, Thecocoelurusis similar to the cervical vertebrae of the Angeac ornithomimosaur, but it isn’t definitely more similar to them than it is to the vertebrae of caenagnathids and so on, and in fact Thecocoelurus shares more characters with caenagnathids and some other taxa than it does with the Angeac ornithomimosaur. It’s a frustrating situation, and again I’d repeat the general idea that we may be expecting too much of a single fragmentary vertebra.

Problems from the Wealden 2: Valdoraptor

I’m more impressed by Allain et al.’s (2014) argument that Valdoraptor – based only on a partial metatarsus and originally confused with the ankylosaur Hylaeosaurus and then regarded as a species of Megalosaurus – is also highly similar to the Angeac ornithomimosaur, and I agree that Valdoraptor should now be reinterpreted as a member of this group. That’s an interesting turn of events for an animal long imagined as a ‘megalosaur’, later suggested to be an allosauroid, and universally considered to be a non-coelurosaur.

Features of the Valdoraptor metatarsus suggested (by Naish 2011) to be diagnostic for this taxon. Photo (c) Natural History Museum, London.

Allain et al. (2014) note that two of three diagnostic characters I suggested for Valdoraptor (Naish 2011) are now invalid, since the characters concerned (a medially projecting distal end of the second metatarsal and a metatarsal III that projects notably further distally than the other metatarsals) are present in other ornithomimosaurs and other coelurosaurs, like tyrannosaurs. Because – at that time – I had Valdoraptor pegged as a non-coelurosaurian tetanuran (Naish 2011), I wasn’t too worried about the form of the metatarsus among coelurosaurs (how you interpret characters is always partially dependent on where you think your taxon fits in the tree of life: a feature that’s unique to a taxon in one part of the tree may be a commonplace and ubiquitous character elsewhere).

The Valdoraptor foot (from Owen's original monograph of 1858, where it's shown as a mirror image relative to the real thing) compared with an ornithomimid ornithomimosaur foot (image by Darren Naish, after Osborn).

However, Allain et al. (2014) agree that one of Valdoraptor’s supposedly diagnostic characters (its mediolaterally compressed metatarsal II) is, among coelurosaurs, uniquely shared by Valdoraptor and the Angeac ornithomimosaur. Here’s where we come to the part where I find myself disagreeing with what the authors have done in their paper.

You’ll recall from above that the Angeac ornithomimosaur is not named, the strong implication being that it represents a wholly new taxon that’ll be named elsewhere. Yet, aren’t the authors on dangerous ground if they’re also saying that Thecocoelurus and Valdoraptor are extremely similar (if not identical) to the Angeac ornithomimosaur? What I mean is: if the Angeac ornithomimosaur shares diagnostic characters with Thecocoelurus or Valdoraptor, and if those taxa are also ornithomimosaurs (as Allain et al. argue they are), then – by definition – the Angeac ornithomimosaur has to be assumed to be synonymous with either or both of those taxa. We’ve already seen above that Thecocoelurus is not obviously closer to the Angeac ornithomimosaur than it is to other theropods, so let’s ignore it for now.

But Valdoraptor? Allain et al. (2014) say that Valdoraptor and the Angeac ornithomimosaur both share a character previously mooted (Naish 2011) as diagnostic for Valdoraptor (this being the compressed form of metatarsal II). But they go on to say that, since this character is also present in other theropods (specifically, noasaurids), it can’t be used to diagnose Valdoraptor. Err, nope.

Recall what I said above about the need to evaluate characters on the basis of where your taxon fits in the tree of life? Allain et al. (2014) are stating that Valdoraptor is an ornithomimosaur: ergo, its mediolaterally compressed metatarsal II has to be evaluated within the context of how this character is distributed within Ornithomimosauria and those lineages closest to it. Noasaurids are nowhere close to ornithomimosaurs in the theropod tree. They’re so distant that any characters shared by noasaurids and ornithomimosaurs (and not present across the intervening nodes of Theropoda) have to be interpreted as obvious convergences [ornithomimid image above by Sebastian Bergmann; Masiakasaurus by Esv]. In other words, if a character present in Valdoraptor is not present in other ornithomimosaurs, and is not primitive for the clade that includes ornithomimosaurs and other coelurosaurs, it has to be interpreted as a unique, diagnostic character for Valdoraptor. So, if the Angeac ornithomimosaur possesses a character that’s otherwise diagnostic for Valdoraptor, then Angeac ornithomimosaur = Valdoraptor.

Let’s see what happens next.

For previous Tet Zoo articles on theropods and other dinosaurs and animals from the Wealden see…

Norell, M. A. & Makovicky, P. J. 1997. Important features of the dromaeosaur skeleton: information from a new specimen. American Museum Novitates 3215, 1-28.

About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

42 Comments

now i understand your holygrailosaurus. wouldn’t oneringosaurus be more accurate? :p

ad for early and lower… is this just convention or is there a reference for this? why chronology and stratigrahy are different? i was following the chart in my thesis, sigh… but i think it reads better: early lower cretaceous instead of early early cretaceous.

Darn those English invasions! Wealden Ornithomimids already in Aquitaine? Well played gentlemen.

Kidding aside, this is fascinating. From the number of fragments they found at Angeac, it looks like we’re going to have lots more data on European ornithomimosaurs now. Oh, and anyone interested in paleoart should check the link to the Ouest Paleo blog. In addition to photos, they have some beautiful reconstructions by the French artist Mazan.

Say you do consider the Angeac critter to represent Valdoraptor. What would be the taxonomically appropriate thing to do if someone subsequently digs out a critter that can’t be distinguished from the Valdoraptor type, but can be distinguished from the Angeac critter due to some feature simply not perserved in the type? Invent new names for both the Angeac and the hypothetical new find? It’d hardly make sense to let the Angeac critter remain Valdoraptor oweni purely because it was happened to be found first.

Thanks for all the comments. darkgabi (comment # 1): the Early/Late vs Lower/Upper thing is indeed a convention that I’ve had drummed into me over the years, both in reviews and editorial comments, and in discussions. I will admit that I’ve never seen it expressed clearly in print.. I do mention it in a book I’m working on right now, as I find it absolutely imperative to refer both to Early and Late sections of time and Lower and Upper chunks of stratigraphy.

Thanks to others (comments # 2, 4-6) for the names. At some point there’s sure to be a something tetzoo (or would it be tetzooi, or what?). Hey, if there’s a Gagadon you bet seven hells that Tet Zoo needs a patronym too

——————-
Say you do consider the Angeac critter to represent Valdoraptor. What would be the taxonomically appropriate thing to do if someone subsequently digs out a critter that can’t be distinguished from the Valdoraptor type, but can be distinguished from the Angeac critter due to some feature simply not perserved in the type? Invent new names for both the Angeac and the hypothetical new find? It’d hardly make sense to let the Angeac critter remain Valdoraptor oweni purely because it was happened to be found first.
——————-

Firstly, I expect a case to be made that the Angeac animal is a different species from Valdoraptor oweni.

Anyway, if the characters currently shared by Valdoraptor oweni and the Angeac animal are hypothetically found in a third animal, and if the Angeac animal and the third animal can be distinguished whereas one or both cannot be distinguished from Valdoraptor oweni, the latter becomes a nomen dubium: it now lacks autapomorphies while the other two do not. In fact, what were once autapomorphies of Valdoraptor oweni would now be synapomorphies of a clade. This is a good example of the ‘character obsolescence’ described by Wilson & Upchurch (2003).

“Naish (2011) listed three characters as diagnostic of Valdoraptor: a mediolaterally compressed metatarsal II, a medially projected distal end of the metatarsal II and the distal extension of the metatarsal III beyond the distal end of the metatarsal II. All these characters have been recognized in the metatarsals of the ornithomimosaur from Angeac.”

So far, so good…

“In the latter, the more complete metatarsal IV is compressed mediolaterally as well, as in Nqwebasaurus (De Klerk et al., 2000; Choiniere et al., 2012), and is D-shaped in cross-section.”

Why “in the latter” [referring to the Angeac ornithomimosaur] in this sentence? They seem to be implying that the character of a mediolaterally compressed metatarsal IV is observed in the Angeac ornithomimosaur and Nqwebasaurus, but not in Valdoraptor. Does this mean that the Agneac ornithomimosaur and Valdoraptor are demonstrably different? That the Valdoraptor metatarsus is not complete enough for this character to be evaluated? In their figure, it doesn’t appear to differ that much in completeness from the Agneac metatarsals.

“Because the metatarsals from Angeac are morphologically almost identical to those of Valdoraptor, and share with them a derived feature unknown in other theropods, the latter taxon is assumed here to be an ornithomimosaur.”

Nowhere in this paper do they mention what this “derived feature unknown in other theropods” is. They state later on that the mediolaterally compressed metatarsal II is unknown in other coelurosaurs, but that it is known in other theropods (noasaurids).

So Valdoraptor seems to share no individual characters exclusively with an ornithomimosaur, even though it may share a combination of characters exclusively with the Agneac ornithomimosaur. I’m not sure if “mediolaterally compressed metatarsal” is a great character to base this hypothesis on- in the ornithomimosaur material I’ve handled, it’s common to see taphonomic variation in this, and they do not seem to state how they draw the line between “compressed” and “not compressed.” But maybe it is a more obviously valid character if you see the material in person.

“In fact, Allain et al. (2014) argue that a whole load of previously problematic Wealden theropod remains all belong to this new kind of ornithomimosaur. Valdoraptor (named for a metatarsus from the Hastings Group) is an ornithomimosaur very similar to the Angeac taxon, so is Thecocoelurus (named for a cervical vertebrae from the Wessex Formation), and so is the famous ‘Calamosaurus tibia’ and several other Wessex Formation hindlimb elements (Allain et al. 2014).”

This is where I have a problem. The Angeac ornithomimosaur comes from Hauterivian–Barremian deposits. Ok. So do Thecocoelurus and Calamosaurus, since they belong to the Wessex Group, or so I understand from Darren’s handy little diagram. It wouldn’t be shocking if Thecocoelurus and the Angeac animal were closely related, maybe even the same species.

But then Valdoraptor, coming from the Hastings Group, must be notably earlier. Still Allain et al. (2014) consider Valdoraptor to be very similar to their ornithomimosaur… They must have in mind a taxon of a higher level than a species, surely? Or is it possible to have a dinosaur species existing for about 15M years? Unless we are talking about late Valanginian and early Hauterivian, all taxa in question having been alive in a short period around 129 M years ago.

One more reason, in my (admittedly non-specialist) opinion to be wary of seeing in the Angeac specimens the long sought after Holygrailosaurus.

All right, I’ve looked up Valdoraptor and it’s indeed late Valanginian, something like 133 Ma. With the Angeac strata dated between 132 and 125 Ma, this still seem a bit early for an identification with Valdoraptor but not absurdly so.

One of the issues with the Allain et al. paper is that they’re deliberately coy/silent on taxonomic status – they deliberately don’t explain what they mean by saying that the Angeac animal is similar to Thecocoelurus and Valdoraptor. Do they mean that these represent the same species, same ‘genus’, same little clade, or what? My feeling is that ‘genus’-level clade is most appropriate: that is, the Angeac animal is most sensibly interpreted (according to Allain et al.’s argument) as a new species of Valdoraptor.

As goes geological longevity (comments # 12 and 13), the idea – hypothetically – that Valdoraptor might have persisted from the late Valanginian, through the Hauterivian and into the Barremian is about plausible based on the geological ranges known or suspected for other Wealden dinosaurs: Baryonyx, for example, is supposed to be present across the same time span.

As for whether the Angeac animal is really referable to Valdoraptor (Brad’s comment # 11), I’m really not sure – but if we follow the logic used in Allain et al.’s paper, this is the ‘correct’ course of action.

Thanks for linking to my post. Now I see what you meant about those differences from Falcarius. Which specimen is that posterior cervical btw? From the label maybe UMNH VP 12469? I’d say you’re right about the pedicular fossae being high up and about the round centrum, both being differences from Thecocoelurus. While the ventral centrum doesn’t flare anteriorly much in your specimen, it does in UMNH VP 14657, so that supports my assertion the character is too variable to use.

What I find interesting is that your figure bears on both differences pointed out by Andrea Cau. First, the neural canal is large in your Falcarius specimen, but small in UMNH VP 14657. Is that because yours is a younger/smaller individual? Second, the Falcarius vertebra looks to have large, simple pneumatic chambers, the camerate condition. This is also what Thecocoelurus looks to have, but Zanno (2010) states “Fragmented specimens reveal the camellate structure of the neural arches and centra, which are comprised almost entirely of thin (approximately 1 mm) bone.” So is Thecocoelurus actually camerate?

Letting the implications sink in… If (and it’s a big if) Valdoraptor, Thecocoelurus and the Angeac beastie are put in the same taxon, shouldn’t the clade be named after Thecocoelurus, as the oldest valid name? That’s what Andrea Cau suggested too if I’m not mistaken.

My apologies to Andrea – I had missed his article until now. Of course, I’ve made another assumption throughout my writing of this article: this being that Allain et al. are right in saying that the Angeac animal is an ornithomimosaur. Andrea raises the fascinating idea that it’s not, but is instead a limusaur-type ceratosaur. Imagine if this is correct: it would be approximately consistent with suggestions that Thecocoelurus is an abelisauroid and Valdoraptor is a non-coelurosaur (both in Naish 2011). Irene: the name Thecocoelurus was published in 1923; Valdoraptor in 1991.

Is the Thecocoelurus holotype camerate? (comment # 15). It sure is. Look at the figures of the polished posterior end (where the specimen can be seen in cross-section) in both Naish et al. (2001) and Naish & Martill (2002): the interior is occupied with a low number of extremely large chambers. The centrum is basically one big space (with perhaps three tiny ones lateral to the ventral part of the neural canal), while the neural arch is occupied by just five spaces.

That’s what I thought too, but look at your figure of Falcarius. One big space in the centrum, several big spaces in the neural arch. Is it possible the fine camellae are unexposed in both? Especially since Thecocoelurus shows numerous small subdivisions in its worn parapophysis? Which reminds me- your Falcarius vertebra seems worn anteriorly so that its anterior surface is actually a cross section. Could this be why the pedicular fossae are so dorsally positioned? Maybe they are more ventral on the anterior surface (as in all the other examined taxa), then their internal vacuity moves upwards as you progress posteriorly through the vertebra?

“but look at your figure of Falcarius. One big space in the centrum, several big spaces in the neural arch.”

Ah, but you’re seeing the Falcarius vertebra in articular view there, not seeing the pneumatic structures internally (plus, you don’t know what’s happening inside the centrum at all – are you confusing the “one big space in the centrum” with the neural canal?). I don’t have any views of the interior structure of that particular vertebra (so far as I recall, damage and poor preservation wholly obscured all the details) and you’d need to go off what’s in the literature (as you’ve noted, Zanno says that Falcarius is camellate in both the neural arches and centra).

I now have a horrible feeling, by the way, that the view of Falcarius we’re seeing there is of a vertebra in posterior view, not anterior. Good job this is a blog post and not a technical paper. The differences I pointed to may still stand, but may not. Gah!! This can’t be resolved without a major study of all the material…

Are we seeing a partially eroded condition in the Falcarius vertebra? It does seem that the bony shelves around the ILP and various fossae have been damaged.

Ah, but note that lateral to your ‘apf’ are two other spaces. These are no doubt internal cavities in the neural arch. Also, the ventral view of your specimen shows the neural arch is unpreserved anteriorly, with no prezygapophyses for instance.

“(plus, you don’t know what’s happening inside the centrum at all – are you confusing the “one big space in the centrum” with the neural canal?)”

No, the light gray space where your “aas” is pointing has no obvious subdivisions.

“I now have a horrible feeling, by the way, that the view of Falcarius we’re seeing there is of a vertebra in posterior view, not anterior.”

The plot thickens! We’ll probably have to wait the complete description of the Angeac specimens to have a clearer view. If only to ascertain that they all represent a unique taxon. It would be interesting if this candidate ‘Holygrailosaurus’ was in fact several different things too…

By the way, Andrea Cau has another article on the Angeac theropod. Including it in his mega-matrix with Thecocoelurus and Valdoraptor leads to a reappraisal of the latter and a congeneric ceratosaurian identity for T. and Angeac… Though of course it’s only a preliminary result, contingent on definitive publication of the French material.

The fact that he finds it also impossible to place V. more precisely than ‘dinosauromorph’ is not making things simpler. When he ignored V. altogether and only uses T. and Angeac in the matrix, they both go fall within ornithomimosaurs again…

I’m feeling like I just swallowed the red pill and start seeing things weird now!

The main reason was that, while it possessed a character suggesting inclusion within Neotetanurae (trapezoidal cross-section to mt III), it lacked characters placing it within Coelurosauria. Furthermore, its width/length ratio (0.3) is most like that of Ceratosaurus, megalosauroids and allosauroids. Ergo, I had it as ‘?Neotetanurae’.

Gabi: This is pretty standard stratigraphic nomenclature (distinction between chronostratigraphic units [bodies of rocks whose boundaries are based on time] and geochronologic units [divisions of geologic time]).

Thanks indeed, Tom. The distinction is pretty logical to me but I keep encountering people who aren’t aware of it. A reviewer of a recent book chapter chastised me, saying “you keep switching between ‘Early’ and ‘Lower’”… ye-es, that’s because I was talking of both time and stratigraphy…

If anyone reads French here, check out this popular science blog post by J. Le Loeuff, one of the authors of the original article. Of course, there’s some mild joking about their find “making tongues wag on the other side of the Channel”! The main thrust of the post is that the Angeac bones change the landscape both for the presence of ornithomimosaurs in Europe and for the interpretation several little Wealden theropods only known from partial remains. There’s also a few ironical asides about the Angeac team doing “vintage paleontology” by describing and comparing specimens without inputing the data in computer programs, “although some people don’t seem to think you can do science without computers”!

The article seems very confident at least that ornithomimosaurs were present in large numbers in Europe during the early Creataceous and that more will be found or reinterpreted that way.

Thanks for bringing attention to that piece, irene It is a bit annoying in being flippant about previous hypotheses regarding the fragmentary Wealden stuff. Furthermore, the silly side-swipes made at computer-assisted phylogenetics are not only unneeded but also ironic given that the therizinosaur and abelisauroid identifications proposed for Thecocoelurus were both made following ‘old-fashioned’ human-led comparison, no digital software involved.

@ Darren:
Well, there was a distinct vibe of “we have the best fossils and we are harder workers, so there” in that article. Silly indeed, it’s not the paleontology Olympics here. And China would probably win those anyway!

There’s also a few ironical asides about the Angeac team doing “vintage paleontology” by describing and comparing specimens without inputing the data in computer programs, “although some people don’t seem to think you can do science without computers”!

Well, you can do a phylogenetic analysis by hand. A tiny one. It just takes you years to calculate the shortest trees by hand and make reasonably sure, by hand, that they really are the shortest ones.

What they’re trying to say is that you don’t have to run a phylogenetic analysis every time you discover a new fossil. While true, it’s beside every point I can see here. Sure, Le Loeuff is saying that some previous attempts to identify the relationships of Thecocoelurus and Valdoraptor have involved phylogenetic analyses, but as Darren says that’s not even true.

From the peanut gallery, I feel obliged to tell John Scanlon way back in #2 that the balrog-crocodile would have a much longer time range than the one-ring-asaurus (the former from before the Ages of the Sun until at least the very latest 3rd Age – the possibility of later survivals cannot be dismissed; the latter from perhaps the mid 2nd Age to the 3rd-4th boundary). I also have to note that the historical record shows that the “end 3rd Age” extinction event and associated geological phenomena actually took place several years before the end of the historical 3rd Age.